RESUMO
We have previously shown that metastases are generally characterized by a core program of gene expression that induces the oxidative energy metabolism, activates vascularization/tissue remodeling, silences extracellular matrix interactions, and alters ion homeostasis. This core program distinguishes metastases from their originating primary tumors as well as from their target host tissues. We hypothesized that organ preference is reflected in additional, site-selective components within the metastatic gene expression programs. Expanding our prior analysis of 653 human gene expression profiles plus data from a murine model, we find that the release from the primary tumor is associated with a suppression of functions that are important for the identity of the organ of origin, such as a down-regulation of steroid hormone responsiveness in the disseminated foci derived from prostate cancer. Metastases adjust to their target microenvironment by up-regulating-even overexpressing-genes and genetic programs that are characteristic of that organ. Finally, alterations in RNA and protein processing as well as immune deviation are common. In the clinic, metastases are mostly treated with the chemotherapy protocols devised for their primary tumors. Adjustments that account for the gene expression differences between primary and metastatic cancers have the potential to improve the currently dismal success rates.
Assuntos
Biomarcadores Tumorais/genética , Neoplasias da Mama/patologia , Neoplasias Renais/patologia , Metástase Neoplásica/genética , Neoplasias da Próstata/patologia , Neoplasias Cutâneas/patologia , Animais , Neoplasias da Mama/genética , Conjuntos de Dados como Assunto , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Renais/genética , Masculino , Melanoma Experimental/genética , Melanoma Experimental/secundário , Camundongos , Metástase Neoplásica/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Neoplasias da Próstata/genética , Neoplasias Cutâneas/genética , Análise Serial de Tecidos , Microambiente Tumoral/genéticaRESUMO
While aberrant expression or splicing of metastasis genes conveys to cancers the ability to break through tissue barriers and disseminate, the genetic basis for organ preference in metastasis formation has remained incompletely understood. Utilizing the gene expression profiles from 653 GEO datasets, we investigate whether the signatures by diverse cancers in various metastatic sites display common features. We corroborate the meta-analysis in a murine model. Metastases are generally characterized by a core program of gene expression that induces the oxidative metabolism, activates vascularization/tissue remodeling, silences extracellular matrix interactions, and alters ion homeostasis. This program distinguishes metastases from their originating primary tumors as well as from their target host tissues. Site-selectivity is accomplished through specific components that adjust to the target micro-environment. The same functional groups of gene expression programs are activated in the metastases of B16-F10 cells to various target organs. It remains to be investigated whether these genetic signatures precede implantation and thus determine organ preference or are shaped by the target site and are thus a consequence of implantation. Conceivably, chemotherapy of disseminated cancer might be more efficacious if selected to match the genetic makeup of the metastases rather than the organ of origin by the primary tumor.
RESUMO
PURPOSE: Despite a sizeable and continuously growing literature on osteopontin and cancer the molecule has not yet found entry into clinical diagnostics. Our identification of spliced variants that are more specific for cancer than the full-length transcript has opened new possibilities for reaching this goal. METHODS: Here we have developed a real-time RT-PCR blood test and evaluated it in a pilot study of breast, lung, pancreatic, gynecologic, and other cancers, compared to non-cancer controls. RESULTS: Osteopontin-b was increased in lung cancers and pancreatic cancers. When applying a cutoff of 2 standard deviations above normal, elevation in osteopontin-b transcripts detected over 40% of lung cancers. Osteopontin-c was increased in gynecologic and pancreatic cancers. Elevation in osteopontin-c of 2 standard deviations above the normal mean value also detected a fraction of breast cancers and lung cancers, suggesting heterogeneity within those types of tumors. Specifically, breast carcinomas were associated with significantly higher levels of osteopontin-c mRNA in the blood than carcinomas in situ. In lung cancer patients, the osteopontin-c blood RNA levels had an increasing trend with tumor grade. CONCLUSIONS: Osteopontin-b and -c in the blood are biomarkers for distinct cancers. Our investigations may have bearing on cancer screening and diagnosis.